Sodium lauryl sulfate is often incorporated in a solid pharmaceutical preparation because of it possesses useful properties capable of accelerating absorption, facilitating dispersion, promoting disintegration and the like. However, recent research found that a pharmaceutical preparation containing sodium lauryl sulfate suffers drawbacks as regards stability. More specifically, the preparation containing sodium lauryl sulfate is easily colored into brown and is gradually deteriorated with time. Further, when the discolored and deteriorated preparation containing sodium lauryl sulfate is administered to a patient or a subject, the preparation displays-undesirable behavior, e.g., the pharmacological substance is dissolved out from the preparation at a higher rate than designed.
Nevertheless, no method for stabilizing a pharmaceutical preparation containing sodium lauryl sulfate has been proposed heretofore.